fix(session-start): scope summary lookup to repository identity (#3160) (#3168)

Windows: compare repo identity via normalizeRepoPath/sameRepoIdentity (8.3 short names, case, separators; inode fallback). All nine windows-latest jobs green on 52587005.

scripts/hooks/session-end.js

@@ -11,7 +11,7 @@
 
 const path = require('path');
 const fs = require('fs');
-const { getSessionsDir, getDateString, getTimeString, getSessionIdShort, sanitizeSessionId, getProjectName, ensureDir, readFile, writeFile, runCommand, stripAnsi, log } = require('../lib/utils');
+const { getSessionsDir, getDateString, getTimeString, getSessionIdShort, sanitizeSessionId, getProjectName, getRepoIdentity, ensureDir, readFile, writeFile, runCommand, stripAnsi, log } = require('../lib/utils');
 const { generateSessionSummary, getContextRemainingPct, getContextThreshold } = require('../lib/llm-summary');
 
 const SUMMARY_START_MARKER = '<!-- ECC:SUMMARY:START -->';
@@ -130,7 +130,8 @@ function getSessionMetadata() {
   return {
     project: getProjectName() || 'unknown',
     branch: branchResult.success ? branchResult.output : 'unknown',
-    worktree: process.cwd()
+    worktree: process.cwd(),
+    repo: getRepoIdentity()
   };
 }
 
@@ -145,16 +146,20 @@ function buildSessionHeader(today, currentTime, metadata, existingContent = '')
   const date = extractHeaderField(existingContent, 'Date') || today;
   const started = extractHeaderField(existingContent, 'Started') || currentTime;
 
-  return [
+  const lines = [
     heading,
     `**Date:** ${date}`,
     `**Started:** ${started}`,
     `**Last Updated:** ${currentTime}`,
     `**Project:** ${metadata.project}`,
     `**Branch:** ${metadata.branch}`,
-    `**Worktree:** ${metadata.worktree}`,
-    ''
-  ].join('\n');
+    `**Worktree:** ${metadata.worktree}`
+  ];
+  if (metadata.repo) {
+    lines.push(`**Repo:** ${metadata.repo}`);
+  }
+  lines.push('');
+  return lines.join('\n');
 }
 
 function mergeSessionHeader(content, today, currentTime, metadata) {

scripts/hooks/session-start.js

@@ -14,6 +14,8 @@ const {
   getSessionSearchDirs,
   getLearnedSkillsDir,
   getProjectName,
+  getRepoIdentity,
+  sameRepoIdentity,
   findFiles,
   ensureDir,
   readFile,
@@ -254,6 +256,7 @@ function pruneExpiredSessions(searchDirs, retentionDays) {
  * Session files written by session-end.js contain header fields like:
  *   **Project:** my-project
  *   **Worktree:** /path/to/project
+ *   **Repo:** /path/to/main-worktree/.git
  *
  * This function reads each session file once, caching its content, and
  * returns both the selected session object and its already-read content
@@ -261,11 +264,18 @@ function pruneExpiredSessions(searchDirs, retentionDays) {
  *
  * Priority (highest to lowest):
  *   1. Exact worktree (cwd) match — most recent
- *   2. Same project name match for legacy sessions without Worktree metadata
- *   3. No injection when sessions belong to a different worktree/project
+ *   2. Repository identity match: the session was recorded in another
+ *      worktree or subdirectory of the same repository. Identity is the
+ *      main worktree's common git dir (issue #3160), taken from the
+ *      recorded **Repo:** field or resolved from the recorded **Worktree:**
+ *      path for older session files. Unrelated repositories never match.
+ *   3. Same project name match for legacy sessions without Worktree/Repo
+ *      metadata
+ *   4. No injection when sessions belong to a different repository
  *
  * Sessions are already sorted newest-first, so the first match in each
- * category wins.
+ * category wins; the scan continues past repository and project matches so
+ * an exact worktree match always takes precedence.
  *
  * @param {Array<Object>} sessions - Deduplicated session list, sorted newest-first.
  * @param {string} cwd - Current working directory (process.cwd()).
@@ -279,7 +289,17 @@ function selectMatchingSession(sessions, cwd, currentProject) {
 
   // Normalize cwd once outside the loop to avoid repeated syscalls
   const normalizedCwd = normalizePath(cwd);
+  const currentRepoId = getRepoIdentity(cwd);
+  const repoIdByWorktree = new Map();
+  const repoIdOfRecordedWorktree = (recordedWorktree) => {
+    if (!repoIdByWorktree.has(recordedWorktree)) {
+      repoIdByWorktree.set(recordedWorktree, getRepoIdentity(recordedWorktree));
+    }
+    return repoIdByWorktree.get(recordedWorktree);
+  };
 
+  let repoMatch = null;
+  let repoMatchContent = null;
   let projectMatch = null;
   let projectMatchContent = null;
   let readableSessions = 0;
@@ -289,9 +309,11 @@ function selectMatchingSession(sessions, cwd, currentProject) {
     if (!content) continue;
     readableSessions++;
 
-    // Extract **Worktree:** field
+    // Extract **Worktree:** and **Repo:** fields
     const worktreeMatch = content.match(/\*\*Worktree:\*\*\s*(.+)$/m);
     const sessionWorktree = worktreeMatch ? worktreeMatch[1].trim() : '';
+    const repoFieldMatch = content.match(/\*\*Repo:\*\*\s*(.+)$/m);
+    const sessionRepo = repoFieldMatch ? repoFieldMatch[1].trim() : '';
 
     // Exact worktree match — best possible, return immediately
     // Normalize both paths to handle symlinks and case-insensitive filesystems
@@ -299,9 +321,25 @@ function selectMatchingSession(sessions, cwd, currentProject) {
       return { session, content, matchReason: 'worktree' };
     }
 
+    // Repository identity match (#3160): the summary lookup is scoped to the
+    // repository, not the cwd path, so a session recorded in worktree A is
+    // eligible in worktree B only when both resolve to the same common git
+    // dir. Unrelated repositories never share.
+    if (!repoMatch && currentRepoId && (sessionRepo || sessionWorktree)) {
+      // The recorded Repo field may carry a different path form than the
+      // live lookup (8.3 short names on Windows runners, case, separators),
+      // so compare with filesystem-identity fallback rather than ===.
+      const sessionRepoId = sessionRepo || repoIdOfRecordedWorktree(sessionWorktree);
+      if (sessionRepoId && sameRepoIdentity(sessionRepoId, currentRepoId)) {
+        repoMatch = session;
+        repoMatchContent = content;
+      }
+    }
+
     // Project name match is only safe for legacy session files written before
-    // Worktree metadata existed. A different explicit Worktree is not a match.
-    if (!projectMatch && currentProject && !sessionWorktree) {
+    // Worktree/Repo metadata existed. A different explicit Worktree or Repo
+    // is not a match.
+    if (!projectMatch && currentProject && !sessionWorktree && !sessionRepo) {
       const projectFieldMatch = content.match(/\*\*Project:\*\*\s*(.+)$/m);
       const sessionProject = projectFieldMatch ? projectFieldMatch[1].trim() : '';
       if (sessionProject && sessionProject === currentProject) {
@@ -311,6 +349,10 @@ function selectMatchingSession(sessions, cwd, currentProject) {
     }
   }
 
+  if (repoMatch) {
+    return { session: repoMatch, content: repoMatchContent, matchReason: 'repo' };
+  }
+
   if (projectMatch) {
     return { session: projectMatch, content: projectMatchContent, matchReason: 'project' };
   }

scripts/lib/utils.js

@@ -135,6 +135,74 @@ function getGitRepoName() {
   return path.basename(result.output);
 }
 
+/**
+ * Get the repository identity for a directory: the canonical (real) path of
+ * the repository's common git dir, which is the main worktree's .git
+ * directory. Every linked worktree of one repository resolves to the same
+ * identity, while unrelated repositories never share one.
+ *
+ * @param {string} [dir] - Directory to resolve from (defaults to process.cwd()).
+ * @returns {string|null} The canonical common git dir, or null when dir is
+ *   not inside a git repository or does not exist.
+ */
+function getRepoIdentity(dir, runCmd = runCommand) {
+  const target = dir || process.cwd();
+  const result = runCmd('git rev-parse --git-common-dir', { cwd: target });
+  if (!result.success || !result.output) return null;
+  const commonDir = path.resolve(target, result.output);
+  try {
+    return fs.realpathSync(commonDir);
+  } catch {
+    return commonDir;
+  }
+}
+
+/**
+ * Normalize a repository identity path for comparison: canonical (real) form
+ * when it exists, forward slashes, no trailing slash, and lowercase on
+ * Windows where the filesystem is case-insensitive. The platform argument
+ * exists so Windows-shaped git output can be tested on any OS.
+ *
+ * @param {string} p - Path to normalize.
+ * @param {string} [platform] - Platform override (defaults to process.platform).
+ * @returns {string} The normalized path, or '' for empty input.
+ */
+function normalizeRepoPath(p, platform = process.platform) {
+  if (!p) return '';
+  let resolved;
+  try {
+    resolved = fs.realpathSync(p);
+  } catch {
+    resolved = path.resolve(p);
+  }
+  const slashed = resolved.replace(/\\/g, '/').replace(/\/+$/, '');
+  return platform === 'win32' ? slashed.toLowerCase() : slashed;
+}
+
+/**
+ * Compare two repository identity paths. String normalization alone is not
+ * enough on Windows CI runners, where TEMP commonly uses an 8.3 short name
+ * (RUNNER~1): Node's realpath keeps the short form while git reports the
+ * long form for the same directory. When the strings differ, fall back to
+ * filesystem identity (device + inode), which is immune to 8.3 names, case
+ * and separators. Fails closed when either path cannot be statted.
+ *
+ * @param {string} a - First identity path.
+ * @param {string} b - Second identity path.
+ * @returns {boolean} True when both paths name the same directory.
+ */
+function sameRepoIdentity(a, b) {
+  if (!a || !b) return false;
+  if (normalizeRepoPath(a) === normalizeRepoPath(b)) return true;
+  try {
+    const sa = fs.statSync(a);
+    const sb = fs.statSync(b);
+    return sa.ino !== 0 && sa.dev === sb.dev && sa.ino === sb.ino;
+  } catch {
+    return false;
+  }
+}
+
 /**
  * Get project name from git repo or current directory
  */
@@ -642,6 +710,9 @@ module.exports = {
   sanitizeSessionId,
   getSessionIdShort,
   getGitRepoName,
+  getRepoIdentity,
+  normalizeRepoPath,
+  sameRepoIdentity,
   getProjectName,
 
   // File operations

tests/hooks/hooks.test.js

@@ -103,6 +103,9 @@ const CLI_RESUME_SESSION_SENTINEL = 'CLI_RESUME_CONTEXT_SHOULD_NOT_BE_INJECTED';
 const CLI_CLEAR_SESSION_SENTINEL = 'CLI_CLEAR_CONTEXT_SHOULD_NOT_BE_INJECTED';
 const DESKTOP_CLEAR_SESSION_SENTINEL = 'DESKTOP_CLEAR_CONTEXT_SHOULD_NOT_BE_INJECTED';
 const PROJECT_ONLY_SESSION_SENTINEL = 'PROJECT_ONLY_CONTEXT_SHOULD_BE_INJECTED';
+const SAME_REPO_WORKTREE_SENTINEL = 'SAME_REPO_WORKTREE_CONTEXT_SHOULD_BE_INJECTED';
+const REPO_FIELD_SESSION_SENTINEL = 'REPO_FIELD_CONTEXT_SHOULD_BE_INJECTED';
+const UNRELATED_REPO_SESSION_SENTINEL = 'UNRELATED_REPO_CONTEXT_SHOULD_NOT_BE_INJECTED';
 
 function buildSessionStartFixture(content, options = {}) {
   const title = options.title ?? '# Session';
@@ -113,11 +116,41 @@ function buildSessionStartFixture(content, options = {}) {
   if (worktree) {
     lines.push(`**Worktree:** ${worktree}`);
   }
+  if (options.repo) {
+    lines.push(`**Repo:** ${options.repo}`);
+  }
   lines.push('', content, '');
 
   return lines.join('\n');
 }
 
+function initGitRepoWithWorktrees(baseDir, worktreeNames) {
+  const mainrepo = path.join(baseDir, 'mainrepo');
+  execFileSync('git', ['init', '-q', mainrepo]);
+  execFileSync('git', ['config', 'user.email', 't@t.local'], { cwd: mainrepo });
+  execFileSync('git', ['config', 'user.name', 't'], { cwd: mainrepo });
+  fs.writeFileSync(path.join(mainrepo, 'README.md'), 'seed\n');
+  execFileSync('git', ['add', '-A'], { cwd: mainrepo });
+  execFileSync('git', ['commit', '-q', '-m', 'seed'], { cwd: mainrepo });
+  const worktrees = {};
+  for (const name of worktreeNames) {
+    const target = path.join(baseDir, name);
+    execFileSync('git', ['worktree', 'add', '-q', '-b', name, target, 'HEAD'], { cwd: mainrepo });
+    worktrees[name] = target;
+  }
+  return { mainrepo, worktrees };
+}
+
+function gitCommonDirRealpath(dir) {
+  const out = execFileSync('git', ['rev-parse', '--git-common-dir'], { cwd: dir, encoding: 'utf8' }).trim();
+  const resolved = path.resolve(dir, out);
+  try {
+    return fs.realpathSync(resolved);
+  } catch {
+    return resolved;
+  }
+}
+
 // Test helper
 function test(name, fn) {
   try {
@@ -145,9 +178,10 @@ async function asyncTest(name, fn) {
 }
 
 // Run a script and capture output
-function runScript(scriptPath, input = '', env = {}) {
+function runScript(scriptPath, input = '', env = {}, cwd = process.cwd()) {
   return new Promise((resolve, reject) => {
     const proc = spawn('node', [scriptPath], {
+      cwd,
       env: { ...process.env, ...env },
       stdio: ['pipe', 'pipe', 'pipe']
     });
@@ -952,6 +986,119 @@ async function runTests() {
     passed++;
   else failed++;
 
+  if (
+    await asyncTest('injects a same-repository session recorded in a different worktree (#3160)', async () => {
+      const isoHome = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-3160-samerepo-home-'));
+      const sessionsDir = getCanonicalSessionsDir(isoHome);
+      fs.mkdirSync(sessionsDir, { recursive: true });
+      fs.mkdirSync(path.join(isoHome, '.claude', 'skills', 'learned'), { recursive: true });
+      const repoBase = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-3160-samerepo-'));
+      const { worktrees } = initGitRepoWithWorktrees(repoBase, ['wt-a', 'wt-b']);
+
+      const sessionFile = path.join(sessionsDir, '2026-02-11-samerepo-session.tmp');
+      fs.writeFileSync(
+        sessionFile,
+        buildSessionStartFixture(SAME_REPO_WORKTREE_SENTINEL, {
+          project: 'wt-a',
+          worktree: worktrees['wt-a']
+        })
+      );
+
+      try {
+        const result = await runScript(path.join(scriptsDir, 'session-start.js'), '', {
+          HOME: isoHome,
+          USERPROFILE: isoHome
+        }, worktrees['wt-b']);
+        assert.strictEqual(result.code, 0);
+        const additionalContext = getSessionStartAdditionalContext(result.stdout);
+        assert.ok(additionalContext.includes(SAME_REPO_WORKTREE_SENTINEL), 'Should inject a session recorded in another worktree of the same repository');
+        assert.ok(result.stderr.includes('(match: repo)'), `Should report repository identity match, stderr: ${result.stderr}`);
+      } finally {
+        fs.rmSync(isoHome, { recursive: true, force: true });
+        fs.rmSync(repoBase, { recursive: true, force: true });
+      }
+    })
+  )
+    passed++;
+  else failed++;
+
+  if (
+    await asyncTest('scopes sessions by recorded repository identity when the worktree path is gone (#3160)', async () => {
+      const isoHome = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-3160-repofield-home-'));
+      const sessionsDir = getCanonicalSessionsDir(isoHome);
+      fs.mkdirSync(sessionsDir, { recursive: true });
+      fs.mkdirSync(path.join(isoHome, '.claude', 'skills', 'learned'), { recursive: true });
+      const repoBase = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-3160-repofield-'));
+      const { mainrepo, worktrees } = initGitRepoWithWorktrees(repoBase, ['wt-b']);
+
+      const sessionFile = path.join(sessionsDir, '2026-02-11-repofield-session.tmp');
+      fs.writeFileSync(
+        sessionFile,
+        buildSessionStartFixture(REPO_FIELD_SESSION_SENTINEL, {
+          project: 'wt-removed',
+          worktree: path.join(repoBase, 'wt-removed'),
+          repo: gitCommonDirRealpath(mainrepo)
+        })
+      );
+
+      try {
+        const result = await runScript(path.join(scriptsDir, 'session-start.js'), '', {
+          HOME: isoHome,
+          USERPROFILE: isoHome
+        }, worktrees['wt-b']);
+        assert.strictEqual(result.code, 0);
+        const additionalContext = getSessionStartAdditionalContext(result.stdout);
+        assert.ok(additionalContext.includes(REPO_FIELD_SESSION_SENTINEL), 'Should match on the recorded common git dir when the recorded worktree path no longer resolves');
+        assert.ok(result.stderr.includes('(match: repo)'), `Should report repository identity match, stderr: ${result.stderr}`);
+      } finally {
+        fs.rmSync(isoHome, { recursive: true, force: true });
+        fs.rmSync(repoBase, { recursive: true, force: true });
+      }
+    })
+  )
+    passed++;
+  else failed++;
+
+  if (
+    await asyncTest('never injects a session from an unrelated repository (#3160)', async () => {
+      const isoHome = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-3160-unrelated-home-'));
+      const sessionsDir = getCanonicalSessionsDir(isoHome);
+      fs.mkdirSync(sessionsDir, { recursive: true });
+      fs.mkdirSync(path.join(isoHome, '.claude', 'skills', 'learned'), { recursive: true });
+      const repoBaseX = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-3160-repox-'));
+      const repoX = initGitRepoWithWorktrees(repoBaseX, ['wt-x']);
+      const repoBaseY = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-3160-repoy-'));
+      const repoY = initGitRepoWithWorktrees(repoBaseY, ['wt-y']);
+
+      const sessionFile = path.join(sessionsDir, '2026-02-11-unrelated-session.tmp');
+      fs.writeFileSync(
+        sessionFile,
+        buildSessionStartFixture(UNRELATED_REPO_SESSION_SENTINEL, {
+          project: 'wt-x',
+          worktree: repoX.worktrees['wt-x'],
+          repo: gitCommonDirRealpath(repoX.mainrepo)
+        })
+      );
+
+      try {
+        const result = await runScript(path.join(scriptsDir, 'session-start.js'), '', {
+          HOME: isoHome,
+          USERPROFILE: isoHome
+        }, repoY.worktrees['wt-y']);
+        assert.strictEqual(result.code, 0);
+        const additionalContext = getSessionStartAdditionalContext(result.stdout);
+        assert.ok(!additionalContext.includes(UNRELATED_REPO_SESSION_SENTINEL), 'Should never inject a session from an unrelated repository');
+        assert.ok(result.stderr.includes('No worktree/project session match found'), `Should log no-match reason, stderr: ${result.stderr}`);
+      } finally {
+        fs.rmSync(isoHome, { recursive: true, force: true });
+        fs.rmSync(repoBaseX, { recursive: true, force: true });
+        fs.rmSync(repoBaseY, { recursive: true, force: true });
+      }
+    })
+  )
+    passed++;
+  else failed++;
+
   if (
     await asyncTest('reports learned skills count', async () => {
       const isoHome = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-skills-start-'));
@@ -1259,6 +1406,7 @@ async function runTests() {
         assert.ok(content.includes(`**Project:** ${project}`), 'Should persist project metadata');
         assert.ok(content.includes(`**Branch:** ${branch}`), 'Should persist branch metadata');
         assert.ok(content.includes(`**Worktree:** ${process.cwd()}`), 'Should persist worktree metadata');
+        assert.ok(content.includes(`**Repo:** ${gitCommonDirRealpath(process.cwd())}`), 'Should persist repository identity metadata');
       } finally {
         fs.rmSync(isoHome, { recursive: true, force: true });
       }

tests/lib/utils.test.js

@@ -7,6 +7,7 @@
 const assert = require('assert');
 const path = require('path');
 const fs = require('fs');
+const os = require('os');
 const { spawnSync } = require('child_process');
 
 // Import the module
@@ -243,6 +244,69 @@ function runTests() {
     assert.ok(name && name.length > 0);
   })) passed++; else failed++;
 
+  // Repository identity tests (#3160 Windows path forms)
+  console.log('\nRepository Identity:');
+
+  if (test('getRepoIdentity resolves a mocked relative git output against dir', () => {
+    const fakeGit = () => ({ success: true, output: '.git' });
+    const id = utils.getRepoIdentity('/definitely/missing/repo', fakeGit);
+    assert.strictEqual(id, path.resolve('/definitely/missing/repo', '.git'));
+  })) passed++; else failed++;
+
+  if (test('getRepoIdentity returns null when git fails', () => {
+    const fakeGit = () => ({ success: false, output: 'not a git repository' });
+    assert.strictEqual(utils.getRepoIdentity('/definitely/missing/repo', fakeGit), null);
+  })) passed++; else failed++;
+
+  if (test('normalizeRepoPath treats Windows-shaped paths equal across case and separators', () => {
+    // Windows-shaped git output: 8.3 short name, backslashes, mixed case.
+    // Runs on any OS; the platform argument selects the case-insensitive rule.
+    const a = 'C:\\Users\\RUNNER~1\\AppData\\Local\\Temp\\repo\\.git';
+    const b = 'c:/users/runner~1/appdata/local/temp/repo/.git';
+    assert.strictEqual(
+      utils.normalizeRepoPath(a, 'win32'),
+      utils.normalizeRepoPath(b, 'win32')
+    );
+  })) passed++; else failed++;
+
+  if (test('normalizeRepoPath strips trailing slashes and keeps case off win32', () => {
+    const a = utils.normalizeRepoPath('X:/Repo/Main/.git/', 'linux');
+    const b = utils.normalizeRepoPath('X:/Repo/Main/.git', 'linux');
+    assert.strictEqual(a, b);
+    assert.ok(!/\.git\/$/.test(a));
+    assert.ok(a.includes('Repo'), 'linux normalization must not lowercase');
+  })) passed++; else failed++;
+
+  if (test('sameRepoIdentity matches a hard link by filesystem identity', () => {
+    // dev+ino fallback: different path strings, same file. This is what
+    // rescues 8.3 short-name versus long-name mismatches on Windows.
+    const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-repoid-'));
+    try {
+      const orig = path.join(dir, 'a');
+      const link = path.join(dir, 'b');
+      fs.writeFileSync(orig, 'x');
+      fs.linkSync(orig, link);
+      assert.ok(utils.sameRepoIdentity(orig, link));
+    } finally {
+      fs.rmSync(dir, { recursive: true, force: true });
+    }
+  })) passed++; else failed++;
+
+  if (test('sameRepoIdentity rejects different files and missing paths', () => {
+    const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-repoid-'));
+    try {
+      const a = path.join(dir, 'a');
+      const b = path.join(dir, 'b');
+      fs.writeFileSync(a, 'x');
+      fs.writeFileSync(b, 'y');
+      assert.ok(!utils.sameRepoIdentity(a, b));
+      assert.ok(!utils.sameRepoIdentity(a, path.join(dir, 'missing')));
+      assert.ok(!utils.sameRepoIdentity('', b));
+    } finally {
+      fs.rmSync(dir, { recursive: true, force: true });
+    }
+  })) passed++; else failed++;
+
   // sanitizeSessionId tests
   console.log('\nsanitizeSessionId:');